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Wow, thanks for the amazing reply. Clearly this is a subject of passion to you. To clarify, I'm a computer scientist and my physics background is sadly very poo

Wow, thanks for the amazing reply. Clearly this is a subject of passion to you. To clarify, I'm a computer scientist and my physics background is sadly very poor, so much of what you say and link to goes straight over my head. But I think I get the gist of it, thanks to your summary: >> So: SR first; then thoughts about accelerated v freely-falling observers where relativistic effects are expected, including some thought experiments and some sketches that could be weakly checked by astronomy; becoming convinced that non-Euclidean geometry could represent some of these effects; then learning (and developing) relevant mathematics; then GR; then modelling systems and predicting behaviours using GR; then early precision astronomical and eventually (and sadly, posthumously) laboratory tests of those. From this I take that Einstein was mainly a theoretician, which is perhaps a little bit surprising. It is to me, because I have an idea of physics as a discipline with a very strong empirical component. In the AI and machine learning community there is a bit of a debate about the lack of a theory of intelligence, or artificial intelligence, to guide research. Turing award winner Yann LeCun for example has argued that a theory is not necessary because very often technological advances precede theoretical understanding. He's used the Wright brothers as an example and claimed there was no theory of aerodynamics before their first powered flight, but I think he's wrong about that: George Caley set the foundations of aerodynamics a good 100 years before the Wrights. I asked my question just because I was curious but as I was reading your answer it occurred to me that it is relevant to that debate, that I'm very interested in (and have my own strong opinions about). Einstein comes across as a powerful example of how far a dedicated, competent theoretician can go without a need for empirical results. A little bit scary to be sure, and certainly a lone theoretician plugging away at a theory on their own will not go very far, there needs to be the right environment, a scientific community that can properly evaluate such work. In any case, despite what LeCun says I am convinced that there can be no true scientific progress without theoretical understanding. Even if empirical results come first, we only really make progress when our understanding of the world improves. But all that is a bit political; apologies if you find that disagreeable. And now I wonder whether Einstein was really one of a kind, as we're taught since school. There must have been others, other physicists, and possibly astronomers, who made progress only based on mathematics and theoretical understanding, and didn't have direct empirical confirmation of their results for a long time; or possibly never -because those results were confirmed after their death; yeah, sad for uncle Albert :( . Thanks again for your erudite and thorough reply!

raattgift 2y ago
There's no real focused thesis below, more a set of reactions to your comment: Einstein wasn't in practice a lone wolf, he worked in academic environments; he focused on three passions and didn't stray much; he worked "on paper" with very few physical artifacts attributed to him; he was extremely successful where his interests took him, even quite late in life where he failed to meet some of his own hopes; while he is a household name in much of the world, there are other well-known names in his areas of interest (that he admired & used the work of); and after he died the work of thousands of others in those areas of interest carried on. > Clearly this is a subject of passion to you Not exactly - the passion here is for physical theories of gravitation, with a side helping of obviously unphysical uses of gravitation (e.g. spacetimes with arbitrary numbers of dimensions), and wrong theories of gravitation. This thread was more history of science, which isn't a passion. It's just that I've read a lot of 20th century scientific papers on gravitation, which are often interesting but rarely of practical relevance. (It also goes into "metahistory" of science or metaphysics or whatever which is even less of a passion, so I'm afraid I won't engage with your summary of LeCun. I'm not familiar with him (yes I know, it's HN, but...), there's no obvious overlapping expertise. I'm not sure I'd get it right if I were to comment much more on the relativist/astrophysicist "dance" I mention below, and I simply would not know what I'm talking about when it comes to AI, computer vision, etc.) > Einstein was mainly a theoretician Yes, very much. We can tie this to the article at the top: late in his career he pursued theories which didn't bear fruit for one reason or another. In astrophysics and physical cosmology there has been centuries of "dance" between theoreticians and experimentalists -- sometimes, the former have 'go look for this particularly' ideas which can pan out; sometimes the latter produce a 'huh, we weren't expecting and can't explain this result'. Theory and observation co-evolve. Again, though that goes into the history and philosophy of science more broadly, and that's too far from my island of comfort. There are many many HN commenters who will share their thoughts on this stuff quite readily. > whether Einstein was one of a kind, as we're taught since school He was, but it doesn't really matter -- he died before there were tools for theoreticians like supercomputers, before the cosmic microwave background was discovered, before neutrinos were observed in a lab, before ultra cold atomic gasses could be made and studied in a lab, before the first practical atomic clock, before the discovery of astrophysical masers, before the first lasers, and so on and so forth, before CCDs, before good slew studies of the "variable universe" <https://www.astronomy.ohio-state.edu/asassn/index.shtml https://www.astronomy.ohio-state.edu/asassn/index.shtml>. Some of this stuff would probably have been harder to invent without his photoelectric effect paper (for which he got the Nobel prize in physics) or special relativity. But if all those tools and techniques had been around when he was at his most intellectually productive, it would have been interesting to see how he would have adapted his thinking, and what he would have chosen to work on. (Not to mention that scientists can collaborate with one another much more easily these days, and don't have to wait for access to experimental results as long as before there was the Internet. Just the way he would do things now day-to-day would be incredibly different. It's really hard to imagine being stuck with the long long lonnnnnnnnnng waits he had to put up with, but on the other hand he wasn't distracted by streaming entertainment, computer games, social media, etc etc, and had more time to fill as a result -- notably while travelling via HORSE (!), train, and ship to academic conferences, instead of flying or being remote.) > There must have been others Sure, physics and the mathematics of physics are totally littered with surnames like Gauss, Laplace, Lagrange, Lorentz, Poincaré, Newton, Leibniz, Galileo -- many of them were "polymaths" that studied many areas of science and even many non-scientific things (for example: economics, social sciences). By comparison,Einstein stuck to his three lanes (thermodynamics, quantum theory, and gravitation), writing down theories that used groundbreaking formulae and theories named for / developed by all of the above and more. Interestingly, one experiment/invention of Einstein's that I do know (there may be others; I just deal in theories he developed alone and with collaborators) came from his interest in thermodynamics: https://en.wikipedia.org/wiki/Einstein_refrigerator https://en.wikipedia.org/wiki/Einstein_refrigerator I would imagine Einstein would have been interested in the cooling of electronic equipment and especially computers, had he lived into the 1980s. He also would likely have been interested in computer display technology (CRTs use and LEDs/OLEDs are related to the photoelectric effect) and digital photography (which has uses in astronomy, obviously). > A lone theoretician plugging away on their own is pretty rare, since it is so easy to get feedback from other theoreticians, results from experimentalists, and so on. There are many single-author theory papers still, but they generally aren't written by recluses. Einstein certainly didn't work in a vacuum, particularly when it came to General Relativity and his later Grand Unified Theory work. He got help from mathematicians and published a number of papers with coauthors. Finally, because he didn't work in a vacuum it is safe to say that if he were suddenly resurrected today with all his previous memories intact, he would have a lot to catch up on to be able to make sense of most papers in quantum mechanics and gravitation. He'd have to learn how to browse the web safely; he'd have to pick up some LaTeX and probably a bit of computer programming. These are all things a modern physics student will pick up no later than their first year at university. There's quite a lot of graduate-level stuff in regular use that postdates Einstein too, that he would have to become familiar with. I'm pretty sure he would still be productive and even prolific very quickly, but he would need help from others practically right away. (That wouldn't be alien: he had help from Hilbert, Levi-Civita, Noether, and many others, during his career). No matter how expert one is in one's "silo", there will always be people much more expert than you in other fields, even closely-related other fields. And even in your "silo" you won't always be preeminent (and even then can learn from others).

raattgift 2y ago

There's no real focused thesis below, more a set of reactions to your comment: Einstein wasn't in practice a lone wolf, he worked in academic environments; he focused on three passions and didn't stray much; he worked "on paper" with very few physical artifacts attributed to him; he was extremely successful where his interests took him, even quite late in life where he failed to meet some of his own hopes; while he is a household name in much of the world, there are other well-known names in his areas of interest (that he admired & used the work of); and after he died the work of thousands of others in those areas of interest carried on. > Clearly this is a subject of passion to you Not exactly - the passion here is for physical theories of gravitation, with a side helping of obviously unphysical uses of gravitation (e.g. spacetimes with arbitrary numbers of dimensions), and wrong theories of gravitation. This thread was more history of science, which isn't a passion. It's just that I've read a lot of 20th century scientific papers on gravitation, which are often interesting but rarely of practical relevance. (It also goes into "metahistory" of science or metaphysics or whatever which is even less of a passion, so I'm afraid I won't engage with your summary of LeCun. I'm not familiar with him (yes I know, it's HN, but...), there's no obvious overlapping expertise. I'm not sure I'd get it right if I were to comment much more on the relativist/astrophysicist "dance" I mention below, and I simply would not know what I'm talking about when it comes to AI, computer vision, etc.) > Einstein was mainly a theoretician Yes, very much. We can tie this to the article at the top: late in his career he pursued theories which didn't bear fruit for one reason or another. In astrophysics and physical cosmology there has been centuries of "dance" between theoreticians and experimentalists -- sometimes, the former have 'go look for this particularly' ideas which can pan out; sometimes the latter produce a 'huh, we weren't expecting and can't explain this result'. Theory and observation co-evolve. Again, though that goes into the history and philosophy of science more broadly, and that's too far from my island of comfort. There are many many HN commenters who will share their thoughts on this stuff quite readily. > whether Einstein was one of a kind, as we're taught since school He was, but it doesn't really matter -- he died before there were tools for theoreticians like supercomputers, before the cosmic microwave background was discovered, before neutrinos were observed in a lab, before ultra cold atomic gasses could be made and studied in a lab, before the first practical atomic clock, before the discovery of astrophysical masers, before the first lasers, and so on and so forth, before CCDs, before good slew studies of the "variable universe" <https://www.astronomy.ohio-state.edu/asassn/index.shtml https://www.astronomy.ohio-state.edu/asassn/index.shtml>. Some of this stuff would probably have been harder to invent without his photoelectric effect paper (for which he got the Nobel prize in physics) or special relativity. But if all those tools and techniques had been around when he was at his most intellectually productive, it would have been interesting to see how he would have adapted his thinking, and what he would have chosen to work on. (Not to mention that scientists can collaborate with one another much more easily these days, and don't have to wait for access to experimental results as long as before there was the Internet. Just the way he would do things now day-to-day would be incredibly different. It's really hard to imagine being stuck with the long long lonnnnnnnnnng waits he had to put up with, but on the other hand he wasn't distracted by streaming entertainment, computer games, social media, etc etc, and had more time to fill as a result -- notably while travelling via HORSE (!), train, and ship to academic conferences, instead of flying or being remote.) > There must have been others Sure, physics and the mathematics of physics are totally littered with surnames like Gauss, Laplace, Lagrange, Lorentz, Poincaré, Newton, Leibniz, Galileo -- many of them were "polymaths" that studied many areas of science and even many non-scientific things (for example: economics, social sciences). By comparison,Einstein stuck to his three lanes (thermodynamics, quantum theory, and gravitation), writing down theories that used groundbreaking formulae and theories named for / developed by all of the above and more. Interestingly, one experiment/invention of Einstein's that I do know (there may be others; I just deal in theories he developed alone and with collaborators) came from his interest in thermodynamics: https://en.wikipedia.org/wiki/Einstein_refrigerator https://en.wikipedia.org/wiki/Einstein_refrigerator I would imagine Einstein would have been interested in the cooling of electronic equipment and especially computers, had he lived into the 1980s. He also would likely have been interested in computer display technology (CRTs use and LEDs/OLEDs are related to the photoelectric effect) and digital photography (which has uses in astronomy, obviously). > A lone theoretician plugging away on their own is pretty rare, since it is so easy to get feedback from other theoreticians, results from experimentalists, and so on. There are many single-author theory papers still, but they generally aren't written by recluses. Einstein certainly didn't work in a vacuum, particularly when it came to General Relativity and his later Grand Unified Theory work. He got help from mathematicians and published a number of papers with coauthors. Finally, because he didn't work in a vacuum it is safe to say that if he were suddenly resurrected today with all his previous memories intact, he would have a lot to catch up on to be able to make sense of most papers in quantum mechanics and gravitation. He'd have to learn how to browse the web safely; he'd have to pick up some LaTeX and probably a bit of computer programming. These are all things a modern physics student will pick up no later than their first year at university. There's quite a lot of graduate-level stuff in regular use that postdates Einstein too, that he would have to become familiar with. I'm pretty sure he would still be productive and even prolific very quickly, but he would need help from others practically right away. (That wouldn't be alien: he had help from Hilbert, Levi-Civita, Noether, and many others, during his career). No matter how expert one is in one's "silo", there will always be people much more expert than you in other fields, even closely-related other fields. And even in your "silo" you won't always be preeminent (and even then can learn from others).